马上就答辩了,项目中遇到个问题,是android项目,用的SQLite数据库。现在有个数据库的方法不会写,具体内容是:通过表中的name字段,查出对应的phonenumber字段。数据库方法不会写,求助一下。
我写了个方法,想让他传进sql语句,就返回该name的phonenumber,帮忙解答下,这么写对嘛
/*
* 操作数据库对象
*/
private SQLiteDatabase mDataBase;
public String queryName(String sql) {
String count;
if (mDataBase == null) {
return 0;
}
Cursor cursor = mDataBase.rawQuery(sql, null);
count = cursor.getString(0);
cursor.close();
return count;
}
------解决方案--------------------
用JDBC的話,只是驅動部份不一樣
- Java code
import java.sql.*;public class Test { public static void main(String[] args) throws Exception { Class.forName("org.sqlite.JDBC"); Connection conn = DriverManager.getConnection("jdbc:sqlite:test.db"); Statement stat = conn.createStatement(); stat.executeUpdate("drop table if exists people;"); stat.executeUpdate("create table people (name, occupation);"); PreparedStatement prep = conn.prepareStatement( "insert into people values (?, ?);"); prep.setString(1, "Gandhi"); prep.setString(2, "politics"); prep.addBatch(); prep.setString(1, "Turing"); prep.setString(2, "computers"); prep.addBatch(); prep.setString(1, "Wittgenstein"); prep.setString(2, "smartypants"); prep.addBatch(); conn.setAutoCommit(false); prep.executeBatch(); conn.setAutoCommit(true); ResultSet rs = stat.executeQuery("select * from people;"); while (rs.next()) { System.out.println("name = " + rs.getString("name")); System.out.println("job = " + rs.getString("occupation")); } rs.close(); conn.close(); }}
------解决方案--------------------
不好意思,对具体操作并不熟悉,只是对SQL有所了解而已。
大致类似于:
public String getPhoneByName(String pName) {
String sql = "Select phonenumber From TABLENAME Where name='" + pName + "'";
String phonenumber;
if (mDataBase == null) {
return 0;
}
Cursor cursor = db.rawQuery(sql, null);
while (cursor.moveToNext()) {
phonenumber = cursor.getString(0); //获取第一列的值,第一列的索引从0开始
}
cursor.close();
db.close();
return phonenumber;
}
参考下吧:
http://www.javaask.com/mobile/android/2011/1116/9180.html
------解决方案--------------------
Cursor c = mDataBase.rawQuery(sql, null);
if(c.moveToFirst()){
for(int i=0;i!=c.getCount();i++){
c.move(i);
phonenumber = c.getString(0);
}
}
------解决方案--------------------
安卓上面注入漏洞,这个好玩。
不过说实在的,要是PHONENUMBER由用户输入还真可能存在。